Lubrication structure in a scroll type compressor

ABSTRACT

The oil passage for lubricating a seal means, which separates a high discharge pressure area inside a compressor and a low pressure area inside the compressor with a surface of a rotating member, can be eliminated. A lip seal  37 , which is interposed between a center housing  12  and a circumferential surface of a rotating shaft  14 , is prevented from being withdrawn from an insertion hole  121  by a circlip  38 . A support portion  122 , which forms a part of the insertion hole  121  and supports the lip seal  37 , extends out into a motor housing  13 . An outlet port  324  of a discharge passage  32  is directed to the top portion of the support portion  122  and the circlip  38.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a lubrication structure in a scroll type compressor.

[0003] 2. Description of the Related Art

[0004] In a compressor disclosed in Japanese Unexamined Patent Publication (Kokai) No. 7-145791, a cylindrical partition wall is provided at the end of a main shaft in order to separate a mist of lubrication oil, which circulates through the compressor together with refrigerant gas, from the refrigerant gas so as to lubricate the portions in the compressor that require lubrication. A discharged gas passing through the flow passages in an electric motor portion reaches the flow passage in the main shaft through a cylinder of the cylindrical partition wall and lubrication oil circulating together with the discharge gas is separated in the cylinder of the partition wall, which rotates with the main shaft.

[0005] However, the constitution described above, in which the partition wall used for separating oil is provided in a compressor, leads to an increase in the number of constituent parts. In a compressor disclosed in Japanese Unexamined Patent Publication (Kokai) No. 1-170779, discharge ports are provided in a driving shaft, which revolves a mobile scroll and a main shaft, and then the gas passing through the discharge ports is designed to be discharged from the circumferential surface of the main shaft to a space inside the electric motor side. A mist of lubrication oil carried together with refrigerant gas, which is discharged from the circumferential surface of the main shaft to the inside space of the electric motor side, is separated by centrifugal force.

[0006] In a compressor disclosed in Japanese Unexamined Patent Publication (Kokai) No. 1-170779, special elements to separate the lubrication oil are not used. The lubrication oil separated is accumulated in a bottom portion in the inside space in the electric motor side. Lubrication for a seal means, which separates a high discharge pressure area inside the compressor and a low pressure area inside the compressor with the surface of a rotating member, is important for the durability of the seal means. However, it is necessary to provide an oil passage, which reaches the location of the seal means from the oil accumulation portion in the bottom portion, in order to carry out the lubrication of the seal means with the lubrication oil accumulated in the bottom portion in the inside space of the electric motor side. Thus adaptation of the oil passage needs a manufacturing procedure, in which the oil passage is constructed, and causes the manufacturing cost of the compressor to increase.

[0007] The objective of the present invention is to eliminate an oil passage for lubricating a seal means which separates the high discharge pressure area inside a compressor and the low pressure area inside the compressor with the surface of a rotating member.

[0008] In the present invention, therefore, a scroll type compressor is employed, wherein: a fixed scroll, on the base of which a fixed scroll wall is formed, is opposed to a mobile scroll, on the base of which a mobile scroll wall is formed; a hermetic space is formed between the mobile scroll wall of the mobile scroll side that periodically revolves without self-rotation and the fixed scroll wall, and the volume of the hermetic space decreases according to the periodical revolution of the mobile scroll; and the rotational force of the rotating shaft is transmitted to a periodical revolution mechanism, which provides the periodical revolution to the mobile scroll, so that the mobile scroll is allowed to periodically revolve. In the first aspect of the present invention, a lubrication structure which comprises a seal means, which separates the discharge pressure area inside the compressor and other pressure area inside the compressor with the surface of a rotating member, and a discharge passage provided inside the rotating member is constituted, wherein an outlet port of the discharge passage is directed to at least one of the support portion supporting the seal means and the seal means.

[0009] The gas flowing through the discharge passage impinges on at least one of the support portion of the seal means and the seal means and the lubrication oil carried by the gas is separated from the gas at the moment it impinges on at least one of the support portion of the seal means and the seal means. The separated lubrication oil lubricates the seal means.

[0010] In another aspect of the present invention, the periodical revolution mechanism comprises an eccentric shaft integrally rotating with the rotating shaft and transmission means for eccentric rotation, which is interposed between the eccentric shaft and the mobile scroll and transmits the eccentric rotation of the eccentric shaft to the mobile scroll, and the discharge passage is formed as a continuous passage which penetrates through the eccentric shaft and the rotating shaft.

[0011] The gas which passes through the discharge passage inside the eccentric shaft and the rotating shaft exits from the discharge passage so that it impinges against at least one of the support portion and the seal means.

[0012] The present invention may be more fully understood from the description of the preferred embodiments of the invention set forth below, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In the drawings:

[0014]FIG. 1(a) and FIG. 1(b) show the first embodiment of the present invention and FIG. 1(a) is a profile cross-sectional view of the entire compressor and FIG. 1(b) is a magnified fragmentary cross-sectional view of the major components of the compressor.

[0015]FIG. 2 is a section view taken along line B-B in FIG. 1(a).

[0016]FIG. 3 is a section view taken along line A-A in FIG. 1(a).

[0017]FIG. 4 is a profile cross-sectional view with the major components magnified in the second embodiment.

[0018]FIG. 5 is a profile cross-sectional view with the major components magnified in the third embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The first embodiment, in which the present invention is embodied, is explained according to FIG. 1(a) and FIG. 1(b) to FIG. 3.

[0020] As shown in FIG. 1(a), a center housing 12 is coupled to a fixed scroll 11 and a motor housing 13 is coupled to a center housing 12. A rotating shaft 14 is rotatably supported by the center housing 12 and the motor housing 13 via radial bearings 15 and 16. The rotation shaft 14 penetrates through the center housing 12 and the radial bearing 15 is inserted into an insertion hole 121 through which the rotating shaft 14 penetrates.

[0021] An eccentric shaft 17 is formed integrally with the rotating shaft 14. The eccentric shaft 17 is inserted into a bushing 19 and a balance weight 18 is fixed to the bushing 19. A mobile scroll 20 is supported by the bushing 19 via a needle bearing 21 so that the mobile scroll 20 is opposed to the fixed scroll 11 and allows a relative rotation thereof. The needle bearing 21 is housed in a cylinder of a cylindrical portion 34, which is provided so as to protrude at the rear side of a mobile scroll base 22 of the mobile scroll 20.

[0022] A fixed scroll base 23 and a fixed scroll wall 24 of the fixed scroll 11, and the mobile scroll base 22 and a mobile scroll wall 25 of the mobile scroll 20 form hermetic spaces S0 and S1, as shown in FIG. 2. The mobile scroll 20 periodically revolves according to the rotation of the eccentric shaft 17, and the balance weight 18 cancels out the centrifugal force caused by the periodical revolution of the mobile scroll 20. The eccentric shaft 17, which rotates integrally with the rotating shaft 14, the bushing 19, the cylindrical portion 34 and the needle bearing 21 interposed between the eccentric shaft 17 and the cylindrical portion 34 of the mobile scroll 20 constitute a periodical revolution mechanism. The cylindrical portion 34, the needle bearing 21 and the bushing 19 constitute a transmitting means for eccentric rotation that transmits the eccentric rotation of the eccentric shaft 17 to the mobile scroll 20.

[0023] As shown in FIG. 1(a), a revolving ring 26 is interposed between the mobile scroll base 22 and the center housing 12. Plural (four in the present embodiment) cylindrical self-rotation preventing pins 27 penetrate through and are fixed to the revolving ring 26. An annular pressure-applied plate 28 is interposed between the center housing 12 and the revolving ring 26. As shown in FIG. 3, self-rotation preventing holes 281, as many as there are self-rotation preventing pins 27, are arranged circumferentially on the pressure-applied plate 28. Self-rotation preventing holes 222, as many as there are self-rotation preventing pins 27, are arranged circumferentially on the mobile scroll base 22. Both the self-rotation preventing holes 281 and 222 are equally spaced at the same angles. The end portion of each self-rotation preventing pin 27 is inserted into the self-rotation preventing holes 281 and 222.

[0024] As shown in FIG. 1(a), a stator 29 is fixed to the inner circumferential surface of the motor housing 13 and a rotor 30 is supported by the rotating shaft 14. Both the stator 29 and the rotor 30 constitute a motor and the rotor 30 and the rotating shaft 14 rotate integrally when electrical energy is supplied to the stator 29.

[0025] The mobile scroll 20 periodically revolves according to the rotation of the eccentric shaft 17 integrally formed with the rotating shaft 14, and the refrigerant gas introduced from an inlet 111 flows between the fixed scroll base 23 and the mobile scroll base 22 from the circumferential sides of both the scrolls 11 and 20. According to the periodical revolution of the mobile scroll 20, the circumferential surfaces of the self-rotation preventing pins 27 slidably comes into contact with the circumferential surfaces of the self-rotation preventing holes 222 and 281. The relation D=d+r is specified, where D is a diameter of the self-rotation preventing holes 222 and 281, d is a diameter of the self-rotation preventing pin 27 and r is a radius of the periodical revolution of the bushing 19. This relation sets the radius of the periodical revolution of the mobile scroll 20 to r, and the revolving ring 26 periodically revolves with a radius half the radius r of the mobile scroll 20.

[0026] The revolving ring 26 is prone to self-rotate spontaneously but, because three or more self-rotation preventing pins 27 are in contact with the inner circumferential surface of the fixedly arranged self-rotation preventing hole 281, the revolving ring 26 never self-rotates. The mobile scroll 20 is prone to self-rotate spontaneously about the central axial line of the bushing 19 but, because the inner circumferential surface of the self-rotation preventing hole 222 on the side of the mobile scroll base 22 is in contact with the three or more self-rotation preventing pins 27 on the revolving ring 26 that does not self-rotate, the mobile scroll 20 never self-rotates about the central axial line of the bushing 19. Therefore, the mobile scroll 20 and the revolving ring 26 periodically revolve without self-rotation. The hermetic spaces S1 and S0 shown in FIG. 2 continue to reduce their volumes according to the periodical revolution of the mobile scroll 20, and converge between the inner end portions 241 and 251 of the scroll walls 24 and 25 of the scrolls 11 and 20.

[0027] As shown in FIG. 1(a), a discharge port 221 is formed on the mobile scroll base 22. The discharge port 221 communicates with the final hermetic space S0. The discharge port 221 is opened and closed by a float valve 31. A discharge passage 32 is formed through the eccentric shaft 17 and the rotating shaft 14. The discharge passage 32 is formed by an axial passage 321 parallel with the axial line 142 of the rotating shaft 14 and a radial passage 322 perpendicular to the axial line 142 thereof.

[0028] A seal member 35 is interposed between the end surface of the cylindrical portion 34 and a balance weight 18. The seal member 35 defines a back pressure chamber 36 in the cylindrical portion 34 together with the mobile scroll base 22 and the balance weight 18. The inlet port 323 of the discharge passage 32 is open to the back pressure chamber 36 and the outlet port 324 of the discharge passage 32 is open to the circumferential surface of the rotating shaft 14.

[0029] As shown in the FIG. 1(b), a lip seal 37 is inserted into the insertion hole 121. The lip seal 37, which is interposed between the center housing 12 and the circumferential surface of the rotating shaft 14 as a rotating member, is adjacent to the radial bearing 15. The lip seal 37 is prevented from being withdrawn from the insertion hole 121 by a circlip 38. The support portion 122, which forms a part of the insertion hole 121 and also supports the lip seal 37, extends into the motor housing 13.

[0030] The outlet port 324 of the discharge passage 32 is directed to the top portion of the support portion 122 and the circlip 38. That is, a part of the outlet port 324 overlappingly faces the top portion of the support portion 122 and the circlip 38 when viewed from the longitudinal direction of the radial passage 322.

[0031] The refrigerant gas compressed due to the reduction in volume of the hermetic spaces S1 and S0 is discharged from the final hermetic space S0 into the motor housing 13 through the discharge port 221, the back pressure chamber 36 and the discharge passage 32. The refrigerant gas in the motor housing 13 is brought to an external refrigerant circuit 33 through a passage 141 in the rotating shaft 14 and an exit 131 on the end wall of the motor housing 13.

[0032] The back pressure chamber 36 in the cylindrical portion 34 becomes a high discharge pressure area and the motor housing becomes a high discharge pressure area Pd. The back side of the mobile scroll base 22 outside the cylindrical portion 34 becomes a low suction pressure area Ps. The seal member 35 prevents pressure leakage between the suction pressure area Ps of the back side of the mobile scroll base 22 and the back pressure chamber 36. The lip seal 37 prevents pressure leakage, which can occur in the area from the discharge pressure area Pd in the motor housing 13, along the circumferential surface of the rotating shaft 14, to the suction pressure area Ps of the back side of the mobile scroll base 22.

[0033] The first embodiment obtains the following effects.

[0034] (1-1)

[0035] The refrigerant gas flowing into the motor housing 13 from the outlet port 324 of the discharge passage 32 partially impinges on the support portion 122 and the circlip 38. The mist of lubrication oil carried by the refrigerant gases is separated from the refrigerant gases through the impingement thereof on the support portion 122 and the circlip 38. Some of the separated lubrication oil lubricates the lip seal 37 located near to the separation area and, therefore, an oil passage exclusively used for the lubrication of the lip seal 37 can be eliminated.

[0036] (1-2)

[0037] The abrasion of the lip seal 37 becomes heavier if the lip seal 37 overlappingly faces the outlet port 324. Therefore the outlet port 324 of the discharge passage 32 is avoided to overlappingly face the lip seal 37. However the refrigerant gas injected from the outlet port 324 is diffused and, accordingly, parts of the refrigerant gases injected from the outlet port 324 impinge directly onto the lip seal 37 and the lubrication oil separated by the impingement readily lubricates the lip seal 37.

[0038] (1-3)

[0039] The refrigerant gas in the discharge passage 32 exits from the circumferential surface of the rotating shaft 14, which is rotating. The arrangement where the refrigerant gas is allowed to exit from the circumferential surface of the rotating shaft 14, which is rotating, encourages the oil separation due to the effect of centrifugal force.

[0040] Next, the second embodiment shown in FIG. 4 is described. The same symbols are used for the same elements as in the first embodiment.

[0041] All parts of the outlet port 324, when viewed from the longitudinal direction of the radial passage 322, overlappingly face the top portion of a support portion 122A. Therefore all the refrigerant gases exiting from the outlet port 324 impinge on the support portion 122A. The arrangement where all the refrigerant gases exiting from the outlet port 324 are allowed to readily impinge on the support portion 122A is advantageous in enhancing the efficiency of oil separation.

[0042] Next, the third embodiment shown in FIG. 5 is described. The same symbols are used for the same elements as in the first embodiment.

[0043] The positions of the radial bearing 15 and the lip seal 37 are exchanged compared to the case of the first embodiment and the outlet port 324 of the discharge passage 32 is open to the circumferential surface of the rotating shaft 14 between the radial bearing 15 and the lip seal 37. All parts of the outlet port 324, when viewed from the longitudinal direction of the radial passage 322, overlappingly face a support portion 122B.

[0044] The third embodiment provides the same effect as that of the second embodiment. In addition, the refrigerant gas exiting from the outlet port 324 passes through between the inner race 151 and the outer race 152 of the radial bearing 15 so that the lubrication of the radial bearing 15 is ideally performed.

[0045] In the present invention the outlet port of the discharge passage 32 in the rotating shaft 14 may be directed toward the lip seal 37.

[0046] The reasonable arrangement in which the back pressure chamber, which has a pressure equal to the discharge pressure, concurrently serves as a part of the discharge passage is provided.

[0047] As mentioned in detail above, because the outlet port of the discharge passage in the rotating member is directed to at least one of the support portion of a seal means and the seal means in the present invention, an excellent effect that the oil passages for lubricating the seal means, which separates the high discharge pressure area inside a compressor and the low pressure area inside the compressor with the surface of the rotating member, can be eliminated.

[0048] While the invention has been described by reference to specific embodiments chosen for the purposes of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention. 

1. A lubrication structure in a scroll type compressor, wherein: a fixed scroll, on the base of which a fixed scroll wall is formed, is opposed to a mobile scroll, on the base of which a mobile scroll wall is formed; a hermetic space, the volume of which decreases according to the periodical revolution of the mobile scroll, is formed between the mobile scroll wall at the mobile scroll side that periodically revolves without self-rotation and the fixed scroll wall; and the mobile scroll is designed so as to periodically revolve when a rotational force of a rotating shaft is transmitted to a periodical revolution mechanism in order to periodically revolve the mobile scroll; comprising a seal means which separates the discharge pressure area inside the compressor and other pressure area inside the compressor with the surface of a rotating member; and a discharge passage provided inside the rotating member; wherein the outlet port of the discharge passage is directed to at least one of the support portion supporting the seal means and the seal means.
 2. A lubrication structure in a scroll type compressor as set forth in claim 1 , wherein the rotating member is a rotating shaft and the seal means is a lip seal.
 3. A lubrication structure in a scroll type compressor as set forth in claim 2 , wherein the outlet port of the discharge passage is open to the circumferential surface of the rotating shaft.
 4. A lubrication structure in a scroll type compressor as set forth in claim 2 , wherein the periodical revolution mechanism comprises an eccentric shaft integrally rotating with the rotating shaft and a transmission means of an eccentric rotation, which is interposed between the eccentric shaft and the mobile scroll and transmits the eccentric rotation of the eccentric shaft to the mobile scroll, and wherein the discharge passage continues in and penetrates through the eccentric shaft and the rotation shaft.
 5. A lubrication structure in a scroll type compressor as set forth in claim 1 of the present invention, wherein a discharge port is provided on the mobile scroll base and the back pressure chamber is provided on the back side of the mobile scroll base and the discharge port is open to the back pressure chamber and the inlet port of the discharge passage is open to the back pressure chamber. 